mirror of https://code.videolan.org/videolan/vlc
256 lines
6.1 KiB
C
256 lines
6.1 KiB
C
/*****************************************************************************
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* tfind.c : implement every t* fuctions
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*****************************************************************************/
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#ifdef HAVE_CONFIG_H
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# include <config.h>
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#endif
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/** search.h is not present so every t* functions has to be implemented */
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#ifndef HAVE_SEARCH_H
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#include <assert.h>
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#include <stdlib.h>
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typedef struct node {
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char *key;
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struct node *llink, *rlink;
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} node_t;
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/* $NetBSD: tdelete.c,v 1.4 2006/03/19 01:12:08 christos Exp $ */
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/*
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* Tree search generalized from Knuth (6.2.2) Algorithm T just like
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* the AT&T man page says.
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*
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* The node_t structure is for internal use only, lint doesn't grok it.
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*
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* Written by reading the System V Interface Definition, not the code.
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*
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* Totally public domain.
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*/
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/* delete node with given key */
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void *
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tdelete(vkey, vrootp, compar)
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const void *vkey; /* key to be deleted */
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void **vrootp; /* address of the root of tree */
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int (*compar) (const void *, const void *);
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{
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node_t **rootp = (node_t **)vrootp;
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node_t *p, *q, *r;
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int cmp;
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assert(vkey != NULL);
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assert(compar != NULL);
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if (rootp == NULL || (p = *rootp) == NULL)
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return NULL;
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while ((cmp = (*compar)(vkey, (*rootp)->key)) != 0) {
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p = *rootp;
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rootp = (cmp < 0) ?
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&(*rootp)->llink : /* follow llink branch */
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&(*rootp)->rlink; /* follow rlink branch */
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if (*rootp == NULL)
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return NULL; /* key not found */
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}
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r = (*rootp)->rlink; /* D1: */
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if ((q = (*rootp)->llink) == NULL) /* Left NULL? */
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q = r;
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else if (r != NULL) { /* Right link is NULL? */
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if (r->llink == NULL) { /* D2: Find successor */
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r->llink = q;
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q = r;
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} else { /* D3: Find NULL link */
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for (q = r->llink; q->llink != NULL; q = r->llink)
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r = q;
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r->llink = q->rlink;
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q->llink = (*rootp)->llink;
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q->rlink = (*rootp)->rlink;
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}
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}
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if (p != *rootp)
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free(*rootp); /* D4: Free node */
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*rootp = q; /* link parent to new node */
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return p;
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}
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/* $NetBSD: tdestroy.c,v 1.2 1999/09/16 11:45:37 lukem Exp $ */
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/*
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* Tree search generalized from Knuth (6.2.2) Algorithm T just like
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* the AT&T man page says.
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*
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* The node_t structure is for internal use only, lint doesn't grok it.
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*
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* Written by reading the System V Interface Definition, not the code.
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*
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* Totally public domain.
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*/
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/* Walk the nodes of a tree */
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static void
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tdestroy_recurse(node_t* root, void (*free_action)(void *))
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{
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if (root->llink != NULL)
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tdestroy_recurse(root->llink, free_action);
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if (root->rlink != NULL)
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tdestroy_recurse(root->rlink, free_action);
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(*free_action) ((void *) root->key);
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free(root);
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}
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void
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tdestroy(vrootp, freefct)
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void *vrootp;
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void (*freefct)(void *);
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{
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node_t *root = (node_t *) vrootp;
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if (root != NULL)
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tdestroy_recurse(root, freefct);
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}
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/* $NetBSD: tfind.c,v 1.5 2005/03/23 08:16:53 kleink Exp $ */
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/*
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* Tree search generalized from Knuth (6.2.2) Algorithm T just like
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* the AT&T man page says.
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*
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* The node_t structure is for internal use only, lint doesn't grok it.
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*
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* Written by reading the System V Interface Definition, not the code.
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*
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* Totally public domain.
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*/
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/* find a node, or return 0 */
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void *
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tfind(vkey, vrootp, compar)
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const void *vkey; /* key to be found */
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const void **vrootp; /* address of the tree root */
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int (*compar) (const void *, const void *);
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{
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node_t * const *rootp = (node_t * const*)vrootp;
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assert(vkey != NULL);
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assert(compar != NULL);
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if (rootp == NULL)
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return NULL;
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while (*rootp != NULL) { /* T1: */
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int r;
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if ((r = (*compar)(vkey, (*rootp)->key)) == 0) /* T2: */
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return *rootp; /* key found */
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rootp = (r < 0) ?
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&(*rootp)->llink : /* T3: follow left branch */
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&(*rootp)->rlink; /* T4: follow right branch */
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}
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return NULL;
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}
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/* $NetBSD: tsearch.c,v 1.5 2005/11/29 03:12:00 christos Exp $ */
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/*
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* Tree search generalized from Knuth (6.2.2) Algorithm T just like
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* the AT&T man page says.
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*
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* The node_t structure is for internal use only, lint doesn't grok it.
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*
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* Written by reading the System V Interface Definition, not the code.
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*
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* Totally public domain.
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*/
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/* find or insert datum into search tree */
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void *
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tsearch(vkey, vrootp, compar)
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const void *vkey; /* key to be located */
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void **vrootp; /* address of tree root */
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int (*compar) (const void *, const void *);
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{
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node_t *q;
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node_t **rootp = (node_t **)vrootp;
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assert(vkey != NULL);
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assert(compar != NULL);
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if (rootp == NULL)
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return NULL;
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while (*rootp != NULL) { /* Knuth's T1: */
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int r;
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if ((r = (*compar)(vkey, (*rootp)->key)) == 0) /* T2: */
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return *rootp; /* we found it! */
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rootp = (r < 0) ?
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&(*rootp)->llink : /* T3: follow left branch */
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&(*rootp)->rlink; /* T4: follow right branch */
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}
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q = malloc(sizeof(node_t)); /* T5: key not found */
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if (q != 0) { /* make new node */
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*rootp = q; /* link new node to old */
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q->key = (void*)vkey; /* initialize new node */
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q->llink = q->rlink = NULL;
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}
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return q;
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}
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/* $NetBSD: twalk.c,v 1.2 1999/09/16 11:45:37 lukem Exp $ */
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/*
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* Tree search generalized from Knuth (6.2.2) Algorithm T just like
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* the AT&T man page says.
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*
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* The node_t structure is for internal use only, lint doesn't grok it.
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*
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* Written by reading the System V Interface Definition, not the code.
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*
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* Totally public domain.
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*/
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/* Walk the nodes of a tree */
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static void
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twalk_recurse(root, action, level)
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const node_t *root; /* Root of the tree to be walked */
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void (*action) (const void *, VISIT, int);
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int level;
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{
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assert(root != NULL);
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assert(action != NULL);
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if (root->llink == NULL && root->rlink == NULL)
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(*action)(root, leaf, level);
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else {
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(*action)(root, preorder, level);
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if (root->llink != NULL)
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twalk_recurse(root->llink, action, level + 1);
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(*action)(root, postorder, level);
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if (root->rlink != NULL)
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twalk_recurse(root->rlink, action, level + 1);
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(*action)(root, endorder, level);
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}
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}
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/* Walk the nodes of a tree */
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void
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twalk(vroot, action)
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const void *vroot; /* Root of the tree to be walked */
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void (*action) (const void *, VISIT, int);
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{
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if (vroot != NULL && action != NULL)
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twalk_recurse(vroot, action, 0);
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}
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#endif // HAVE_SEARCH_H
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